Metallized film capacitors for use in inverters have been recently developed to have a small size, high performance, and low cost. The metallized film capacitors used in the inverters are required to withstand high working voltages, large electric currents, and to have large capacitances. To meet these requirements, a case-molded metallized film capacitor including plural capacitor elements which are connected in parallel to each other and which are molded in a case is put into a practical use. Such case-molded metallized film capacitor is required to have a large mechanical strength, a large thermal resistance, a high water resistance, and oil resistance.
FIG. 9 is a front sectional view of a conventional case-molded capacitor. As shown in FIG. 9, capacitor element 101 is provided by winding a metallized film having evaporated metal electrodes provided on one surface or both surfaces of the metalized film, such that the evaporated metal electrodes face each other across a dielectric film. Sprayed-metal electrodes 103 are provided on both ends of the capacitor element, or sprayed metal coating are provided on the electrodes of both ends of each capacitor element. Plural capacitor elements 101 are arranged to be attached to each other. Busbars 102 made of copper plates are electrode terminals for external connection attached to both ends of capacitor element 101. Busbars 102 are connected to sprayed-metal electrodes 103 formed on both ends of each of capacitor elements 101. Respective ends of the busbars extend upward and are exposed from metal case 104. Metal case 104 having capacitor elements 101 placed therein is made of aluminum. Insulating sheet 105 made of, e.g. polypropylene film having a thickness of 200 μm is placed inside metal case 104 so as to prevent metal case 104 and capacitor elements 101 from short-circuiting and to prevent metal case 104 and busbars 102 connected to the capacitor elements from short-circuiting. Mold resin 106 fills metal case 104 to mold, insulate, and fix the capacitor elements 101 connected via busbars 102 in case 104 except for a portion of electrode terminal 102a. 
Patent document 1 is known as a prior art document related to the present invention.
This conventional case-molded capacitor may cause heat to remain in capacitor elements 101 depending on property of material of mold resin 106 when it is used with a large ripple current or at a high temperature to require heat dissipation of capacitor element 101. The heat remaining in capacitor elements 101 decreases virtual breakdown voltage (BDV) of capacitor element 101, thus deteriorating electrical characteristics of the capacitor.
Patent Document 1: JP2006-253280A